1. Field of the Invention
This invention relates to a printer, and more particularly, to an apparatus for feeding a printing media, such as a printing sheet or paper, to a printer having a plurality of toner printing units arranged along a feeding path of the printing sheet to transfer, in turn, color images of yellow (Y), magenta (M), cyan (C), and black (B), respectively, to the printing sheet.
2. Description of the Related Art
A printer including a plurality of toner printing units, such as used for printing, in turn, various colors, for example, yellow (Y), magenta (M), cyan (C), and black (B), respectively, arranged along a feeding path of the printing sheet to obtain a full color image on the printing sheet is known, and such a printer is disclosed, for example, in Japanese Unexamined Patent Publication (Kokai) No. 62-145262, in which a plurality of toner printing units are arranged along a sheet feeding path. Each of the toner printing units comprises a rotatable photoconductor drum, and around this photoconductor drum are arranged, in turn, an charger unit for charging the photoconductor drum, an optical depositing unit for forming a latent image on the photoconductor drum, a developing unit for changing the latent image to a toner image, a transferring unit for transferring the toner image on the photoconductor drum onto the printing sheet, and a cleaner for removing remaining toner from the photoconductor drum. The printing sheet is fed along a horizontal sheet feeding path by grippers mounted on a gripper feeding chain for gripping a leading edge of the printing sheet, and a plurality of air suction belts are arranged between the toner printing units to support the printing sheet in a horizontal state when the printing sheet is fed in the feeding direction.
In such a sheet feeding apparatus known in the prior art, however, the air suction belts must be arranged lower than the photoconductor drum by at least a thickness of the grippers. Therefore, the printing sheet may be easily bent or deformed while it is fed along the sheet feeding path. Namely, an exact horizontal state of the printing sheet cannot be guaranteed, and thus the transferring or printing positions of the printing sheet do always coincide in the respective toner printing units.